Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Before
After
Before
After
Before
AfterFast, Reliable Home Additions & ADU Across Shady Hollow
A home addition or ADU in Shady Hollow typically runs $45,000 to $130,000, and the biggest wildcard isn’t lumber or labor. It’s the trees. Shady Hollow was laid out in the 1980s and 90s specifically to preserve its mature live oak and cedar elm canopy, which means a Heritage Tree ordinance review can add months to your timeline before the first trench is cut. Tom Barrett and his sons know exactly how to navigate that process in 78739, because they’ve done it on lots from Slaughter Lane to the western cul-de-sacs. If you’re weighing an in-law suite, a garage conversion, or a second story, call (877) 610-1318 and we’ll walk the lot with you before you spend a dollar on plans.
Why Barrett & Sons Construction Is Shady Hollow’s Preferred Home Additions & ADU Company
We’re not a franchise dispatching strangers from out of state. Barrett & Sons has been owner-operated since 1998, and Tom Barrett’s name, address, and license number are published where anyone can look them up. Shady Hollow homeowners call us because our crews show up in uniform, background-checked, and the person who shook your hand at the estimate is the same person answering the phone when you call about a change order. The Home Additions & ADU team works in Shady Hollow almost every week, which means we know what the City of Austin Urban Forestry division will flag on your lot before you pay an arborist to tell you.
Ask anyone on your street, or look up the license number yourself. We pull permits and get inspections signed on every eligible job, because the permit inspector works for you, not for me. That’s why I like him. And every scope change, every allowance, every price adjustment arrives as a written change order before a single nail moves. An allowance that isn’t on paper is a surprise waiting for a date.
Calls are answered by a live person 24/7, not a voicemail box. We live twenty minutes from Shady Hollow, and if something’s not right, Tom wants to know about it. Not next month. That week.
Our Home Additions & ADU Services in Shady Hollow
ADU Design & Permitting
Shady Hollow’s 78739 zoning sits under Austin’s ADU rules, which have loosened in recent years but still trigger site-specific reviews that stall homeowners who try to go it alone. We handle the full design and permitting package, including the arborist report and critical root zone plan that Austin’s Heritage Tree ordinance requires on nearly every lot with a 19-inch-plus trunk. If your live oak is within 25 feet of the proposed slab, that single tree dictates your setbacks, your foundation type, and sometimes whether the ADU fits at all.
Garage Conversion ADU
A garage conversion in Shady Hollow usually runs $30,000 to $80,000, and it’s often the fastest path to an income suite or a comfortable space for aging parents because you’re working inside an existing footprint. But the original 1983-to-1998 slab-on-grade garages here frequently lack proper stem walls and moisture barriers, which means we’re often cutting and repouring sections before framing begins. One more thing: if the garage sits under a cedar elm canopy, even the flatwork patch can need an arborist sign-off.
New Detached ADU
A new detached ADU in Shady Hollow typically lands between $90,000 and $220,000, driven heavily by foundation and tree-protection costs. The lots here sit on the Balcones Escarpment transition, where Blackland Prairie clay meets fractured limestone, and that’s one of the worst slab-heaving profiles in the Austin metro. We over-engineer the foundation on every detached ADU, because a two-inch heave in July is a lawsuit waiting on a cracked wall in December. If the ADU footprint touches the critical root zone of a protected oak, budget an extra fortnight just for the Urban Forestry review.
Junior ADU & Interior Conversion
For a family member who’s staying close but wants their own door, a Junior ADU carved from the back of a two-story Shady Hollow home is a sharp option, often $45,000 to $90,000 depending on plumbing runs and egress. We see a lot of these in the brick-veneer homes off Brodie Lane where the original floor plan left a formal living room nobody uses. The old insulation standards from the early 90s are nowhere near current Austin energy code, so count on re-insulating the converted space from the studs out.
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Trusted Brands We Service in Shady Hollow
We install premium materials you can look up, not mystery brands off a van. On Shady Hollow additions and ADUs, we regularly spec Simonton windows for their air-infiltration ratings under the Austin energy code updates, and PGT impact units where a structure sits exposed to storm-driven debris off the escarpment. Ply Gem trim and siding hold up better than wood composite under the area’s drought-to-downpour swings. Because crews are in Shady Hollow weekly, our lead times on these products are tighter than what a crew from Buda or Kyle can promise, and our free second opinion on any written estimate applies here without a trip charge inside Travis County.
Common Home Additions & ADU Problems We See in Shady Hollow Homes
- Heritage Tree stop-work delays. A cedar elm or live oak with a 19-inch trunk turns any foundation, addition, or flatwork project into a two-agency review, and we’ve seen DIY-minded homeowners buy plans only to learn the ADU has to shrink by 200 square feet to clear the critical root zone. We pull the arborist report before the first sketch gets drawn.
- Slab heaving on the clay. The Blackland Prairie clay beneath 78739 expands and contracts violently between June drought and September rain, and the original 1980s slab-on-grade foundations were poured thinner than anything allowed today. Any addition needs a geotech look and often pier remediation beneath the existing slab.
- Outdated insulation and air sealing. Homes built between 1983 and 1998 in Shady Hollow often carry R-13 walls and R-30 attic insulation, well below what Austin’s current code requires. A second-story addition is the moment to fix the thermal envelope below it, or the new upstairs room will sweat while the original first floor leaks air.
- Watershed impervious cover limits. Shady Hollow falls under the Slaughter and Williamson Creek watershed ordinances, which cap how much of your lot can be covered by roof and driveway. Adding a detached ADU plus a walkway can push you over the limit, which then requires stormwater mitigation, which adds real dollars you won’t see on a Buda contractor’s bid.
Pricing for Home Additions & ADU in Shady Hollow, TX
Here’s what we’re seeing from recent Shady Hollow estimates. A garage conversion ADU runs $30,000 to $80,000. A Junior ADU or interior conversion lands between $45,000 and $90,000. A new detached ADU runs $90,000 to $220,000, with tree protection and foundation work often representing 25-35% of the total. A full second-story addition or sizeable room addition lands between $45,000 and $130,000, and if the existing slab needs piering beneath the new load path, that’s extra, and you’ll see it as a written change order before we touch it. Every estimate is line-itemed. Every allowance is in writing. Call (877) 610-1318 for a free walkthrough, and if you already have a written bid from anyone else, bring it. We’ll give you a free second opinion, no trip charge inside the county.
We Also Serve Cities Near Shady Hollow
From our work across Shady Hollow, our crews regularly head a few miles south to Buda, up to Austin proper, east to Kyle, and west to Bee Cave. Tree rules change at the county line, and we keep sharp on every jurisdiction. If you’re also thinking through the adjacent spaces, we handle Kitchen Remodeling in Shady Hollow and Bathroom Remodeling in Shady Hollow with the same written-change-order discipline.
Serving Shady Hollow, TX - Our Local Coverage Area
We’re based in the Shady Hollow area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs - Home Additions & ADU in Shady Hollow
In Shady Hollow, expect $45,000 to $130,000 for a room addition or second story, $30,000 to $80,000 for a garage conversion, and $90,000 to $220,000 for a new detached ADU. The numbers climb faster here than in Buda or Kyle because of tree-protection compliance, slab heaving, and watershed impervious cover caps. Call (877) 610-1318 for a line-itemed estimate specific to your lot, free of charge.
Yes, every ADU and addition in Shady Hollow requires City of Austin permits, and on virtually every 78739 lot a Heritage Tree ordinance review with an ISA-certified arborist report before foundation work can begin. We pull all permits and get every inspection signed before we call the job done. The permit inspector works for you, not for me.
A garage conversion typically runs 3 to 5 months once permits clear, while a detached ADU runs 6 to 10 months, with the tree-protection review often adding several weeks before construction starts. We’ll put the schedule in writing with your contract, and the 90-Day Done Right Promise means if anything isn’t right after closeout, one call brings Tom back.
Only if you change the scope, and even then every adjustment arrives as a written change order before work proceeds. No surprise invoices at the end. An allowance that isn’t on paper is a surprise waiting for a date, so we keep every allowance and every scope line on paper from day one. Call (877) 610-1318 to schedule your free estimate.
Yes, we cover all of 78739, from the homes along Slaughter Lane to the western cul-de-sacs near the escarpment and the streets around the school district boundaries. If you’re inside Shady Hollow, we show up, no trip charge inside the county.
Written by Tom Barrett, Owner at Barrett & Sons Construction, serving Shady Hollow and surrounding communities since 1998.